How important is the first charge, NI-MH??

[Anders]

"Problem is that many of the more expnsive chargers will not do a forming C/10 charge. You really need a dumb charger for this not a peak charger."

From another forum, what do you say?

Anders

 

[bwaites]

Very important for cells that will require high outputs. We charge the 1650 CBP cells in the USL at .1A for 20 hours, then slow discharge, then .5 amp charge, then 1 amp discharge, then 1 amp charge and then full dishcharge.

Seems to work.

On the other hand, I have used tons of cells for less critical output with no forming charge and had no problems.

Dumb chargers aren't the best way to do this, a smart charger with a programmable rate is.

Bill

 

[TinderBox (UK)]

a dumb charger is the only way your going to get the best capacity from you ni-mh cells.

all smart chargers, and i mean all, to greater or lesser extent have problems charging new battery`s.

I have about 10 smart chargers at least.

the last charger i bought was an cheap dumb charger with a 160ma charge rate, for charging new battery`s and old cells with voltage so low that a smart charger rejects it.

regards.

 

[SilverFox]

Hello TinderBox,

:devil: My Schulze does a great job and has no problems doing a forming charge on new cells... :devil:

Tom

 

[bwaites]

My Triton has no problems either!

Bill

 

[wptski]

bwaites:

The Triton, y/n! Some RC users have reported that at 100ma setting with new cells, it terminated early, so they suggest setting the sensitivity to zero and time it.

SilverFox:

At .1A charge setting with the Schulze there is no time limit, max capacity limit or termination either, so it is a dumb charger at that rate. That's one thing that I don't like about that charger, the time limit, it forces you at times to a higher charge setting to avoid the time limit of four hours for Ni-MH.

 

[bwaites]

I've had no problems with it doing so.

Of course, I've only done about 500 cells like this, so ?, maybe I'll have problems later.

Bill

 

[SilverFox]

Hello Bill,

At 0.25 amps there is also no time limit with the Schulze...

Tom

 

[BentHeadTX]

I do the 200mA charge/100mA discharge test mode on my V32 BC-900 and it works well although it takes awhile. Then I jump up to 500mA charge/250mA discharge test cycle and top it off with a 1000mA charge/500mA discharge test mode. Three cycles should be OK?

 

[TinderBox (UK)]

I belive the Schulze is a $250 dollar RC style charger, with more settings than you can throw a stick at.

I dout the majority of cps use chargers anywhere near that price.

most cpf users prob use charger that cost $50 or less.

the triton is prob very similar to the Schulze, it is reported to do a very poor charge in auto mode.

most people want an $50 or less charger, and all the smart chargers i have of in that price range terminate charge early, to one extent or another with new cells.

a still say a simple timed dumb charger is best for the first charger and then you can use your smart charger after that.

regards.

 

[BentHeadTX]

Thanks Tinderbox,
I use the Cadex at work to apply the 0.1 charge rate for the first charges and the BC-900 to test at higher rates after the initial charges.

 

[GTI]

Hello all,

Can anyone tell me what is forming?

Thank you
GTi

 

[Anders]

Thanks a lot for the answers, nice to have all theese experts here.

Anders

 

[TinderBox (UK)]

you know when you buy anything rechargable nowerdays it usually tells you to charge it overnight or for about 14 hours. even though the full charge indicator may come on in about three hours this only applies to ni-cd or ni-mh cells.

the first charge formats the cell or forms it like streaching a piece of elastic.

you want it to streach as far as possible but without causing damage to the cell by causing it to overheat.

if your gadget has a lin-ion cell inside you can use it a soon as the charger indicates that it is full as lin-ion cells dont need to be formated.

regards.

 

[pae77]

I wonder if anyone knows whether this old Panasonic 5 hour NiMh charger I got in a package deal at Costco a couple of years or so ago is a dumb charger that would be good for doing the initial forming charge? The model is BQ-345A. Output is DC 2.8V 320mA/140mAX2.

 

[Anders]

PAE77:
This is what i found:
-------------------------------------------------------------
NEVER BUY PANASONIC CHARGERS WITH PANASONIC BATTERIES
THEY GET AS HOT AS 170-180 F and this is almost
close to boiling point of water.

TOO HOT... KILLS THE BATTERIES TOO.

GET REAL CHARGERS GET SLOW CHARGERS

BEST COMBO IS SANYO ON PLANET IF MADE I N JAPAN
DO NOT GET CHINA STUFF FOR nimh BATTERIES
MOST CHEATING GOING ON THERE for china made stuff.

in any case, even if made in JAPAN
IGNORE PANASONIC LIKE A DISEASE
CAN BE FATAL
TAKE IT OFF MARKET AND SUE THEM PLEASE
-----------------------------------------------------------
Maybe this is a bad charger?

Anders

 

[TinderBox (UK)]

I googling to find you an answer on you charger question and found this warning on amazon.

http://www.amazon.com/gp/product/B00008ZPN5/?tag=cpf0b6-20

a dumb charger has a low charge rate, mine is 160ma and has not timer, so you have to remember to turn it off.

but charging at such a low rate, even if you leave it on for twice a long you will probabley not have a problem with todays hi capacity cells.

i use a digital countdown time that rings a alarm after a set time.

regards.

 

[wptski]

Most all meltdowns of La Crosse BC-900 v32 chargers were with newer high capacity cells over 2000mAh charged at 200ma rate. That should tell that these newer high capacity cells are just not the same.

I had some questions about charging these newer cells on my Schulze 330d charger. Matthias Schulze answered that these newer higher capacity cells have such a high internal resistance that even Sanyo doesn't publish the specs! Because of this, chargers have a hard time calculating quick charger currents. He went on to suggest charging to at least 1C to insure that the charge would terminate properly. You need a rock solid clamped type holder too! I've just lately ran into problems using Radio Shack 4xAA back to back type not the flat 4xAA holders but haven't narrowed it down to one of them or all of them! :shrug:

I use this most often for forming: Pro Former

 

[TinderBox (UK)]

nice little charger, but at $44.95, most cpf members won`t buy one.

do what i did, buy an $4.99 dumb charger and just time the charge.

I just charger an 2500mah cell at 160ma for around 20hrs.

if you forget, to switch off, the charge rate is so low it won`t hurt the cells.

regards.

 

[jtr1962]

I have a relevant question. In the event you don't form the cells first time around, can you do so later by first discharging the cell completely, and then slow-charging it as suggested?